Among hospital patients that have surgery, it is estimated that approximately 2 percent develop a surgical site infection (SSI), and among those who develop an SSI, it is estimated that approximately 3 percent die as a result. It is a problem known in the art that unclean medical instruments are one direct cause of SSIs. Despite scrupulous adherence to cleaning and sterilization standards, which include a multi-step process of rinsing, scrubbing and sterilization, instruments may fail to become sufficiently clean or sterile.
Cleaning and sterilization of cannulated instruments is particularly challenging. A cannulated medical instrument contains a hollow shaft, known as a lumen, running straight through the center of the instrument, through which a surgeon may introduce, position, manipulate and/or remove surgical and biological material directly to or from the surgical site inside the patient's body. Operating through the center of a medical instrument allows a surgeon to operate with great precision and through a smaller incision, creating the potential for reduced trauma and a better surgical outcome. However, it is a problem known in the art that the interior of a narrow lumen can be difficult to clean and sterilize.
Every surface of a medical instrument must be cleaned and sterilized between uses, including lumen's interior surface. Rinsing and scrubbing steps in the cleaning process should remove physical debris, but then the entire interior surface of the lumen must reach sterilization temperature in an autoclave in order to effectively kill pathogens and meet sterilization requirements. Changing standards in how instruments are sterilized in an autoclave (e.g., reduced cycle time in the autoclave; increased use of autoclave bins with few access holes to allow superheated steam to directly contact instruments) have made sterilization more difficult to achieve than ever before, and some prior art handles may no longer be able to meet sterilization requirements.
Autoclave tests of prior art cannulated medical instruments have demonstrated that instruments with narrow interior diameters in the lumen take longer to reach sterilization temperature in the middle of the lumen as compared to instruments with wider interior diameters in the lumen. This may be attributed to the greater volume of the structure surrounding a narrower lumen. An instrument with the same overall exterior dimensions but with a wider lumen has thinner walls around the lumen and thus has less mass to absorb heat and impede the rise in temperature as the instrument is heated to sterilization temperature.
It is desirable to have a medical instrument which offers the surgical benefits of a cannulated instrument but which is capable of being sterilized and cleaned in a manner that meets sterilization requirements and thus prevents SSIs.
It is desirable to have a cannulated medical instrument with a wider lumen or internal chamber to increase the effectiveness of sterilization in an autoclave.
It is further desirable to have a cannulated medical instrument with less mass surrounding the lumen or internal chamber to further increase the effectiveness of sterilization in an autoclave.